The herbivorous sauropod dinosaurs of the Jurassic and Cretaceous periods were the largest terrestrial animals ever, surpassing the largest herbivorous mammals by an order of magnitude in body mass. Several evolutionary lineages among Sauropoda produced giants with body masses in excess of 50 metric tonnes by conservative estimates. With body mass increase driven by the selective advantages of large body size, animal lineages will increase in body size until they reach the limit determined by the interplay of bauplan, biology, and resource availability. There is no evidence, however, that resource availability and global physicochemical parameters were different enough in the Mesozoic to have led to sauropod gigantism.

We review the biology of sauropod dinosaurs in detail and posit that sauropod gigantism was made possible by a specific combination of plesiomorphic characters (phylogenetic heritage) and evolutionary innovations at different levels which triggered a remarkable evolutionary cascade. Of these key innovations, the most important probably was the very long neck, the most conspicuous feature of the sauropod bauplan. Compared to other herbivores, the long neck allowed more efficient food uptake than in other large herbivores by covering a much larger feeding envelope and making food accessible that was out of the reach of other herbivores. Sauropods thus must have been able to take up more energy from their environment than other herbivores.

The long neck, in turn, could only evolve because of the small head and the extensive pneumatization of the sauropod axial skeleton, lightening the neck. The small head was possible because food was ingested without mastication. Both mastication and a gastric mill would have limited food uptake rate. Scaling relationships between gastrointestinal tract size and basal metabolic rate (BMR) suggest that sauropods compensated for the lack of particle reduction with long retention times, even at high uptake rates.

The extensive pneumatization of the axial skeleton resulted from the evolution of an avian-style respiratory system, presumably at the base of Saurischia. An avian-style respiratory system would also have lowered the cost of breathing, reduced specific gravity, and may have been important in removing excess body heat. Another crucial innovation inherited from basal dinosaurs was a high BMR. This is required for fueling the high growth rate necessary for a multi-tonne animal to survive to reproductive maturity.

The retention of the plesiomorphic oviparous mode of reproduction appears to have been critical as well, allowing much faster population recovery than in megaherbivore mammals. Sauropods produced numerous but small offspring each season while land mammals show a negative correlation of reproductive output to body size. This permitted lower population densities in sauropods than in megaherbivore mammals but larger individuals.

Our work on sauropod dinosaurs thus informs us about evolutionary limits to body size in other groups of herbivorous terrestrial tetrapods. Ectothermic reptiles are strongly limited by their low BMR, remaining small. Mammals are limited by their extensive mastication and their vivipary, while ornithsichian dinosaurs were only limited by their extensive mastication, having greater average body sizes than mammals.

/pdf/biology-of-the-sauropod-dinosaurs-the-evolution-of-gigantism-1nwgigb74u.pdf

Biology of the sauropod dinosaurs: the evolution of gigantism.

This disclosure presents systems for total reflection x-ray fluorescence measurements that have x-ray flux and x-ray flux density several orders of magnitude greater than existing x-ray technologies. These may therefore useful for applications such as trace element detection and/or for total-reflection fluorescence analysis. The higher brightness is achieved in part by using designs for x-ray targets that comprise a number of microstructures of one or more selected x-ray generating materials fabricated in close thermal contact with a substrate having high thermal conductivity. This allows for bombardment of the targets with higher electron density or higher energy electrons, which leads to greater x-ray brightness and therefore greater x-ray flux. The high brightness/high flux source may then be coupled to an x-ray reflecting optical system, which can focus the high flux x-rays to a spots that can be as small as one micron, leading to high flux density.

X-ray surface analysis and measurement apparatus

Energy-dispersive X-ray fluorescence spectrometer for analysis of conventional and micro-samples: Preliminary assessment

We present a micro-x-ray fluorescence (XRF) system having a high-brightness x-ray illumination system with high x-ray flux and high flux density. The higher brightness is achieved in part by using x-ray target designs that comprise a number of microstructures of x-ray generating materials fabricated in close thermal contact with a substrate having high thermal conductivity. This allows for bombardment of the targets with higher electron density or higher energy electrons, which leads to greater x-ray flux. The high brightness/high flux x-ray source may then be coupled to an x-ray optical system, which can collect and focus the high flux x-rays to spots that can be as small as one micron, leading to high flux density at the fluorescent sample. Such systems may be useful for a variety of applications, including mineralogy, trace element detection, structure and composition analysis, metrology, as well as forensic science and diagnostic systems.

X-ray fluorescence system with high flux and high flux density

This study investigated the distribution of the elemental constituents of Mg-based implants at various stages of the degradation process in surrounding bone tissue, with a focus on magnesium (Mg), as the main component of the alloy, and yttrium (Y), due to its potential adverse health effects. The measurements were performed on the implant-bearing thin sections of rat bone in a time series of implant degradation between one and 18 months. Micro X-ray fluorescence analysis (μXRF) with a special spectrometer meeting the requirements for the measurements of low-Z elements was used. It was found that the migration and accumulation behaviour of implant degradation products is element-specific. A sharp decrease in Mg was observed in the immediate vicinity of the interface and no specific accumulation or aggregation of Mg in the adjacent bone tissue was detected. By contrast, Y was found to migrate further into the bone over time and to remain in the tissue even after the complete degradation of the implant. Although the nature of Y accumulations must still be clarified, its potential health impact should be considered.

https://www.mdpi.com/1996-1944/9/10/811/pdf

µXRF Elemental Mapping of Bioresorbable Magnesium-Based Implants in Bone.

Since most micro-spectrometers are operated in air, up to now only mapping of medium and higher Z elements was possible with micro X-ray fluorescence analysis (µ-XRF). Though for some applications (e.g.: biological- and geological samples, samples from art and archeology) the extension to light elements is of great interest. Therefore µ -XRF measurements using a polycapillary lens mounted inside a vacuum chamber have been performed. X-rays from a 2kW high power diffraction tubes (Mo and Cr anode) as well as from a low power 50 W Pd-anode tube were focused by means of the polycapillary X-ray optics. The polycapillary adjustment was performed with a combination of an X/Y stage and a gimbal allowing 3 translation and 2 rotation movements. With this setup it was possible to produce an X-ray spot of about 40µm in diameter at the sample surface. Sample motion is performed by an x-y-z-micrometer driven stage PC controlled. The position dependent fluorescence signal was collected by a Peltier cooled energy dispersive detector (10 mm2 Silicon Drift type) with an ultrathin window (300nm) allowing the detection down to oxygen. Scanning measurements have been carried out on various samples of human femural bone. Results from an area scan (500 x 1100 µm 2 ) across the transition zone of trabecular- and cortical bone are presented, including the distribution of O, P, Ca, and Zn. To compare the performance of the different anode X-ray tubes single point measurements on NIST glass (soda lime glass) have been performed with regard to light element detection. A comparison of results using the different excitation conditions of Mo-L and Pd-L on various samples will be presented with excellent conditions regarding excitation, detection, and background using a vacuum chamber for µ-XRF.

Micro xrf of light elements using a polycapillary lens and an ultra thin window silicon drift detector inside a vacuum chamber

Combined X-ray fluorescence and absorption micro-tomography on U- and Pu-rich particles

To investigate mineral and trace elements in human bone the micro-fluorescence facility installed at the bending magnet Beamline L at HASYLAB, Hamburg, was used, focusing our interest on differences in concentrations of lead between the outer (Substantia Compacta: SC) and inner bone region (Substantia Spongiosa: SS). Among mineral and heavy elements, Pb has been proven to exert adverse effects in men with T1/2 in human bone that ranges between 6-12 years. Thus, bone of a hip-operated adult patient was sliced perpendicular to the SC/SS transition and investigated. For the Pb detection, excitation with the synchrotron white spectrum to excite the K-shell and a monochromatic radiation obtained with the Si(111) channel cut to measure the Lshell fluorescence was compared. The monochromatic excitation delivered the best peak to background ratio and detection limits in sub ppm range. While the K-shell excitation did not reveal sufficient results, L-shell fluorescence was adequate with detection limits for Pb of 0.8ppm for white, and of 0.25ppm for monochromatic excitation respectively. From the medical point of view in the investigated bone sections, Pb, Ca, Fe and Zn were found in higher concentrations in SS than in SC, while Br and Ni, Cu seemed to be lower in the SS than in the SC area.

Sr-xrf investigation of human bone

A.R.Pyzalla, N.Z 3 3 3 4 5 oeger , C.Streli , P.Wobrauschek , R.Simon , P.M.Sander , E.Chinea–Cano TU Wien, IMST, Karlsplatz 13-308, 1040 Wien, Austria; now at Max-Plan ny; ck-Institute for Iron Research, Max-Planck-Straße 1, D-40237 Düsseldorf, Germa Atomic Institute of the Austrian Universities, Stadionallee 2, 1020 Wien, Austria; ANKA, Inst. f. Synchrotronstrahlung, Forschungszentrum Karlsruhe, D-76344 Eggenstein-Leopoldshafen, Germany; University of Bonn, Institute of Palaeontology, Nusseallee, D-53115 Bonn, Germany; 6 IAEA, Seibersdorf Laboratories, Seibersdorf , Austria

Synchrotron XRF Determination of Element Distribution in Fossilized Sauropod Bones

Sr-xrf i nvestigation of human bone

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